JP4974344B2 - Liquid crystal sealant and liquid crystal display cell using the same - Google Patents

Description

  The present invention relates to a liquid crystal sealant used for bonding a TFT substrate and a CF substrate and enclosing a liquid crystal therein, and a liquid crystal display cell using the same.

  In recent years, liquid crystal display cells have been applied to large display screens such as televisions, and demand for them has been increasing. This liquid crystal display cell is manufactured by encapsulating liquid crystals in upper and lower glass substrates fixed with resin. In recent years, a liquid crystal dropping method in which liquid crystal is dropped into a weir made of resin and then bonded to cure the resin has been put into practical use. In any of the manufacturing methods, the upper and lower bases are bonded by a liquid crystal sealant that is in direct contact with the liquid crystal, and the liquid crystal is also enclosed. Therefore, the liquid crystal sealant is required to have a characteristic that the liquid crystal is not contaminated even when it comes into contact with the liquid crystal. At the same time, from the viewpoint of production line tact, a product having a long pot life while being fast-curing is required. In addition, long-term reliability of the produced panel is an important issue, and in particular, moisture resistance reliability is a characteristic required for a sealant.

  Various proposals have been made as sealing agents having these characteristics (Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5), but those having substantially all of the characteristics have not yet been completed. Not. In addition, in the liquid crystal panel market, where high definition is advancing, further improvement in the characteristics of the sealing agent is required, and there is a problem that the characteristics of the sealing agent cannot keep up with the progress.

Japanese Patent No. 2754004 Japanese Patent No. 3583326 JP 2001-89743 A JP-A-10-273644 JP 2004-61925 A

  The present invention provides a liquid crystal sealant that has low contamination to liquid crystals throughout the process, is excellent in coating workability to a substrate, pot life, and is excellent in moisture resistance reliability.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention by paying attention to the use of aromatic hydrazide and aliphatic hydrazide as thermosetting components.
That is, the present invention relates to the following (1) to (9).

(1) A liquid crystal sealant comprising (a) an epoxy resin, (b) an aromatic hydrazide compound and (c) an aliphatic hydrazide compound.
(2) The liquid crystal sealant according to (1), wherein the aromatic hydrazide compound as the component (b) is an aromatic dihydrazide and the aliphatic hydrazide compound as the component (c) is an aliphatic dihydrazide.
(3) In addition to the component (a), the component (b), and the component (c), (d) a photocurable resin and (e) a radical photopolymerization initiator as described in (1) or (2) above Liquid crystal sealant.
(4) The liquid crystal sealing agent according to item (3), wherein the photocurable resin as the component (d) is an acrylic resin.
(5) The liquid crystal sealant according to (3) or (4), wherein the photocurable resin as the component (d) is an epoxy acrylate resin.
(6) The liquid crystal sealing agent according to any one of (1) to (5), further comprising (f) a silane coupling agent.
(7) The liquid crystal sealing agent according to any one of (1) to (6), further comprising (g) an inorganic filler having an average particle diameter of 3 μm or less.
(8) The liquid crystal sealing agent according to any one of (1) to (7), wherein the viscosity is 250 Pa · s or less.
(9) A liquid crystal display cell sealed with a cured product obtained by curing the liquid crystal sealing agent according to any one of (1) to (8).

  The liquid crystal sealant of the present invention has low contamination to the liquid crystal, excellent workability for application to the substrate and pot life, has a fast curing property, and has a good pot life. Excellent moisture resistance reliability. Therefore, by using this sealing agent, it is possible to easily manufacture a liquid crystal display panel with excellent reliability.

Hereinafter, the present invention will be described in detail.
The epoxy resin (a) that can be used in the present invention is not particularly limited, but is preferably a bifunctional or higher functional epoxy resin, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, Phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, bisphenol F novolac epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin Hydantoin type epoxy resin, isocyanurate type epoxy resin, phenol novolac type epoxy resin having triphenolmethane skeleton, diglycidyl etherified product of bifunctional phenols, two governments Diglycidyl ethers of alcohols, and their halides, and the like hydrogenated product. Among these, bisphenol type epoxy resin and novolac type epoxy resin are preferable from the viewpoint of liquid crystal contamination.

  The amount of hydrolyzable chlorine in the epoxy resin used in the present invention is 600 ppm or less, preferably 300 ppm or less. When the amount of hydrolyzable chlorine exceeds 600 ppm, the contamination of the liquid crystal sealant with respect to the liquid crystal becomes a problem. The amount of hydrolyzable chlorine is quantified by, for example, dissolving about 0.5 g of epoxy resin in 20 ml of dioxane, refluxing with 5 ml of 1N KOH / ethanol solution for 30 minutes, and titrating with 0.01N silver nitrate solution. Can do. The content of the epoxy resin (a) in the liquid crystal sealant is about 5 to 50% by weight.

  The component (b) used in the present invention is not particularly limited as long as it is an aromatic hydrazide compound. For example, salicylic acid hydrazide, benzoic acid hydrazide, 1-naphthoic acid hydrazide, terephthalic acid dihydrazide, isophthalic acid dihydrazide 2,6-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,2,4-benzenetrihydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, pyromellitic acid tetrahydrazide, and the like. . In the present invention, a difunctional aromatic dihydrazide is preferable from the balance of curing reactivity and latent, and isophthalic acid dihydrazide is particularly preferable.

  The component (c) used in the present invention is not particularly limited as long as it is an aliphatic hydrazide compound. For example, form hydrazide, acetohydrazide, propionic acid hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid Dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, 1,4-cyclohexanedihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N, N'-hexamethylenebissemicarbazide, citric acid trihydrazide, nitriloacetic acid trihydride Dihydrazides having a valine hydantoin skeleton such as hydrazide, cyclohexanetricarboxylic acid trihydrazide, 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydantoin, etc. I can make it. In the present invention, a difunctional aliphatic dihydrazide is preferable from the balance of curing reactivity and latent, and adipic acid dihydrazide is particularly preferable.

 The average particle size of these hydrazide compounds is preferably 3 μm or less, more preferably 2 μm, because if the average particle size is too large, it may cause a failure such as inability to form a gap when the upper and lower glass substrates are bonded together when manufacturing a narrow gap liquid crystal cell. It is as follows. Similarly, the maximum particle size is preferably 8 μm or less, more preferably 5 μm or less. This particle size was measured with a laser diffraction / scattering type particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd .; LMS-30).

  In the liquid crystal sealant of the present invention, the content of the aromatic hydrazide compound of component (b) is preferably 0.20 to 0.80 equivalent to the epoxy equivalent of the epoxy group of the epoxy resin of component (a), Especially preferably, it is 0.4-0.6 equivalent. The content of the aliphatic hydrazide compound of component (c) is also preferably 0.20 to 0.80 equivalent, particularly preferably 0.4 to the epoxy equivalent of the epoxy group of the epoxy resin of component (a). ~ 0.6 equivalents.

The photo-curable resin (d) used in the present invention is not particularly limited as long as the elution to liquid crystal is low, but acryloyl such as urethane acrylate, (meth) acrylic ester and epoxy (meth) acrylate. And compounds having a group as a functional group (acrylic resin) and the like, specifically, benzyl methacrylate, cyclohexyl methacrylate, glycerol dimethacrylate, glycerol triacrylate, EO-modified glycerol triacrylate, pentaerythritol acrylate, trimethylolpropane triacrylate, Examples include tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate, phlorogricinol triacrylate, and the like. Among these, epoxy (meth) acrylate resins are particularly preferable from the viewpoint of liquid crystal contamination. This epoxy acrylate resin or epoxy methacrylate resin (d) component can be obtained by esterifying acrylic acid or methacrylic acid to an epoxy resin having at least two epoxy groups in the molecule. This synthesis reaction can be performed by a generally known method. For example, epoxy resin having a predetermined equivalent ratio of acrylic acid or methacrylic acid as a catalyst (for example, benzyldimethylamine, triethylamine, benzyltrimethylammonium chloride, triphenylphosphine, triphenylstibine, etc.) and a polymerization inhibitor (for example, methoquinone, Hydroquinone, methylhydroquinone, phenothiazine, dibutylhydroxytoluene and the like) are added and the esterification reaction is performed at 80 to 110 ° C., for example. Examples of the epoxy resin having at least two epoxy groups in the molecule include bisphenol A type epoxy resins, alkyl-substituted bisphenol A type epoxy resins, alkylene oxide-added bisphenol A type epoxy resins, bisphenol F type epoxy resins, Alkyl substituted bisphenol F type epoxy resin, alkylene oxide added bisphenol F type epoxy resin, bisphenol S type epoxy resin, alkyl substituted bisphenol S type epoxy resin, alkylene oxide added bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy Resin, biphenyl type epoxy resin, naphthalene type epoxy resin, glycidylamine type epoxy resin, dicyclopentadiene type epoxy resin , Silicone-modified epoxy resin, urethane-modified epoxy resin, rubber-modified epoxy resin, bisphenol A-type epoxy resin, alkyl-substituted bisphenol A-type epoxy resin, alkylene oxide-added bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, alkyl Substituted bisphenol F-type epoxy resins, alkylene oxide-added bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, alkyl-substituted bisphenol S-type epoxy resins, and alkylene oxide-added bisphenol S-type epoxy resins are preferred.
In the present invention, the content of the photocurable resin (d) in the liquid crystal sealant is about 20% by weight to 80% by weight.

  The radical photopolymerization initiator (e) used in the present invention is not particularly limited as long as it is a radical type initiator, and examples thereof include benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc. Can be mentioned. Further, by using a photo-radical polymerization initiator having a radical polymerization reactive group and a radical generating group in one molecule represented by the formula (1), it is possible to realize further low liquid crystal contamination.

  In the liquid crystal sealant of the present invention, the compounding ratio of the component (e) radical photopolymerization initiator to the component (d) is preferably 0.01 to 5 parts by weight, particularly preferably 100 parts by weight of the component (d). 0.1 to 3 parts by weight. If the amount of radical generating photoradical polymerization initiator is less than 0.01 parts by weight, the photocuring reaction is not sufficient, and if it exceeds 5 parts by weight, the amount of initiator is too much and the liquid crystal is contaminated by the initiator or cured resin. Deterioration of characteristics becomes a problem.

  The liquid crystal sealing agent of the present invention preferably contains a silane coupling agent (f) in order to improve the adhesive strength. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Methoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3- Aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3 Chloropropyl methyl dimethoxy silane, silane coupling agents such as 3-chloropropyl trimethoxysilane. These silane coupling agents may be used in combination of two or more. Among these, in order to obtain better adhesive strength, the silane coupling agent is preferably a silane coupling agent having an amino group. By using a silane coupling agent, an adhesive strength is improved and a liquid crystal sealing agent having excellent moisture resistance reliability can be obtained. The content of the silane coupling agent (f) in the liquid crystal sealant is about 0.05 to 3% by weight.

  Examples of the inorganic filler (g) that can be used in the present invention include fused silica, crystalline silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, Magnesium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably molten Silica, crystalline silica, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, aluminum silicate, more preferably fused silica, Silica, alumina, talc. Two or more of these inorganic fillers may be mixed and used. The average particle diameter is preferably 3 μm or less, and more preferably 2 μm or less, because if the average particle size is too large, it becomes a cause of defects such as failure to form a gap when the upper and lower glass substrates are bonded together when manufacturing a narrow gap liquid crystal cell. The particle size was measured with a laser diffraction / scattering type particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd .; LMS-30).

  The content of the inorganic filler (g) that can be used in the present invention in the liquid crystal sealant is usually 5 to 40% by weight, preferably 15 to 30% by weight. When the content of the inorganic filler is lower than 5% by weight, the adhesive strength to the glass substrate is lowered, and the moisture resistance reliability is inferior, so that the decrease in the adhesive strength after moisture absorption may be increased. In addition, when the content of the inorganic filler is more than 40% by weight, the filler content is too much, so that the liquid crystal cell gap may not be formed because it is difficult to be crushed.

  If necessary, the liquid crystal sealing agent according to the present invention may further contain additives such as an organic solvent, an organic filler, a pigment, a leveling agent, and an antifoaming agent.

  The viscosity of the liquid crystal sealant according to the present invention is preferably 250 Pa · s or less. When the viscosity is higher than this, handling properties such as dispensing properties are inferior. Further, when the pressure is 250 Pa · s or less, it is possible to cope with a seal coating method such as screen printing, which is considered to greatly affect the productivity of the panel.

  In order to obtain the liquid crystal sealant of the present invention, the component (a), the component (e), and the component (f) are first dissolved and mixed with the component (a) as necessary. Next, a predetermined amount of inorganic filler (g) component, further component (b), component (c) and organic filler, antifoaming agent, leveling agent and the like are added to the mixture, and a known mixing device, For example, the liquid crystal sealing agent of the present invention can be produced by uniformly mixing with a three roll, sand mill, ball mill or the like.

The liquid crystal display cell of the present invention is a cell in which a pair of substrates having predetermined electrodes formed on a substrate are arranged opposite to each other at a predetermined interval, the periphery is sealed with the liquid crystal sealant of the present invention, and liquid crystal is sealed in the gap. is there. The kind of liquid crystal to be sealed is not particularly limited. Here, the substrate is composed of a combination of substrates made of at least one of glass, quartz, plastic, silicon, etc. and having light transmission properties. For example, in the case of the liquid crystal injection method, after adding a spacer (gap control material) such as glass fiber to the liquid crystal sealant of the present invention, the liquid crystal sealant is applied to one of the pair of substrates by a dispenser or the like. To do. At this time, one or two injection ports for injecting liquid crystal are opened. Thereafter, the other glass substrate is overlapped and a gap is formed. After forming the gap, it cures at 90 to 130 ° C. for 1 to 2 hours to create an empty cell. After injecting liquid crystal from the injection port, the liquid crystal display cell is sealed by sealing the injection port with a sealing agent (UV curable resin). I can get it.
In the case of the liquid crystal dropping method, after adding a spacer (gap control material) such as glass fiber to the liquid crystal sealing agent of the present invention, the liquid crystal sealing agent is applied to one of the pair of substrates by a dispenser or the like, Liquid crystal is dropped inside the weir of the liquid crystal sealant, and the other glass substrate is overlaid in a vacuum to create a gap. After forming the gap, the liquid crystal seal portion is irradiated with ultraviolet rays by an ultraviolet irradiator to be photocured. Ultraviolet irradiation amount is preferably ^{500mJ / cm 2 ~6000mJ / cm 2} , more preferably the dose of 1000mJ / cm ² 2~4000mJ / cm ² is preferred. Then, the liquid crystal display cell of this invention can be obtained by hardening at 90-130 degreeC for 1-2 hours. The liquid crystal display cell of the present invention thus obtained has no display defects due to liquid crystal contamination, and has excellent adhesion and moisture resistance reliability. Examples of the spacer include glass fiber, silica beads, and polymer beads. The diameter varies depending on the purpose, but is usually 2 to 8 μm, preferably 4 to 7 μm. The amount used is usually 0.1 to 4 parts by weight, preferably 0.5 to 2 parts by weight, more preferably about 0.9 to 1.5 parts by weight, based on 100 parts by weight of the liquid crystal sealant of the present invention. is there.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Synthesis Example 1 Synthesis of Photoradical Polymerization Initiator (e) Represented by Formula (1) 2-isocyanate ethyl methacrylate (Showa Denko Co., Ltd., Karenz MOI) 155 g, 2-hydroxy-4′-hydroxyethoxy- 224 g of 2-methylpropiophenone (manufactured by Ciba Specialty Chemicals Co., Ltd., IRG-2959) was placed in a reaction vessel, and 0.76 g of methylhydroquinone was added thereto as a polymerization inhibitor. This was heated up to 80 degreeC and stirred as it was for about 26 hours. The obtained reaction solution was dissolved in a mixed solvent of methyl isobutyl ketone and toluene and washed with water. Thereafter, methyl isobutyl ketone and toluene were distilled off, and recrystallization using ethyl acetate and n-hexane was performed to obtain a photoradical polymerization initiator represented by the formula (1).

Example 1
160 parts by weight of epoxy acrylate of bisphenol A epoxy resin (Dow Chemical Co., DER-332; epoxy equivalent 175 g / eq), DER-332 (Dow Chemical Co .; epoxy equivalent 175 g / eq) as an epoxy resin 40 parts by weight, photo radical polymerization initiator represented by formula (1) obtained in Synthesis Example 1 (2-isocyanatoethyl methacrylate and 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl The reaction product of 2-methylpropan-1-one) was dissolved by heating at 90 ° C. to obtain a resin solution. After cooling to room temperature, 8 parts by weight of adipic acid dihydrazide (trade name ADH-S; jet mill pulverized grade made by Otsuka Chemical Co., Ltd.), isophthalic acid dihydrazide (trade name IDH-S; Otsuka Chemical) 9 parts by weight of a jet mill pulverized grade manufactured by Co., Ltd. and 25 parts by weight of alumina (manufactured by SPC-Al, average particle size 1.0 μm), rubber (manufactured by Osaka Kasei, Paraloid EXL-2655) And 5.8 parts by weight of the average particle diameter μm), and kneaded with three rolls to obtain the liquid crystal sealant of the present invention. The viscosity (25 ° C.) of the liquid crystal sealant was 190 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Example 2
Epoxy resin DER-332 (manufactured by Dow Chemical Co., Ltd .; epoxy equivalent 175 g / eq) 100 parts by weight of adipic acid dihydrazide (trade name ADH-S; Otsuka Chemical Co., Ltd. jet mill pulverized grade is further pulverized with a jet mill. 20 parts by weight, isophthalic acid dihydrazide (trade name IDH-S; further pulverized jet mill pulverized grade made by Otsuka Chemical Co., Ltd.) 22.5 parts by weight, alumina (manufactured by SPC-Al, 25 parts by weight of an average particle size of 1.0 μm) and 5.8 parts by weight of rubber (Osaka Kasei Co., Ltd., Paraloid EXL-2655, average particle size of μm) are added and kneaded with three rolls, and the liquid crystal sealant of the present invention. Got. The viscosity (25 ° C.) of the liquid crystal sealant was 110 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 1
A liquid crystal sealant was obtained in the same manner as in Example 1 except that only 8 parts by weight of adipic acid dihydrazide was used as a thermosetting agent and that isophthalic acid dihydrazide was removed. The viscosity was 160 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 2
A liquid crystal sealant was obtained in the same manner as in Example 1 except that only 9 parts by weight of isophthalic acid dihydrazide was used as the thermosetting agent, and adipic acid dihydrazide was omitted. The viscosity was 160 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 3
A liquid crystal sealant was obtained in the same manner as in Example 1 except that only 18 parts by weight of adipic acid dihydrazide was used as a thermosetting agent and that isophthalic acid dihydrazide was removed. The viscosity was 190 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 4
A liquid crystal sealant was obtained in the same manner as in Example 1 except that only 28 parts by weight of salicylic acid hydrazide (manufactured by Otsuka Chemical Co., Ltd.) was used as the thermosetting agent, and adipic acid dihydrazide and isophthalic acid dihydrazide were excluded. The viscosity was 220 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 5
A liquid crystal sealant was obtained in the same manner as in Example 2 except that only 20 parts by weight of adipic acid dihydrazide was used as a thermosetting agent, and isophthalic acid dihydrazide was omitted. The viscosity was 50 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 6
A liquid crystal sealant was obtained in the same manner as in Example 2 except that only 22.5 parts by weight of isophthalic acid dihydrazide was used as a thermosetting agent, and adipic acid dihydrazide was omitted. The viscosity was 60 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 7
A liquid crystal sealant was obtained in the same manner as in Example 2 except that only 40 parts by weight of adipic acid dihydrazide was used as a thermosetting agent, and isophthalic acid dihydrazide was omitted. The viscosity was 60 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Comparative Example 8
A liquid crystal sealant was obtained in the same manner as in Example 2 except that only 45 parts by weight of isophthalic acid dihydrazide was used as a thermosetting agent and adipic acid dihydrazide was omitted. The viscosity was 110 Pa · s (R-type viscometer (manufactured by Toki Sangyo Co., Ltd.))

Liquid crystal contamination test 0.1 g of 3 kinds of sealing agents (Examples 1 and 2 and Comparative Examples 1, 2, 3, 4, 5, 6, 7, and 8) was put into a sample bottle and irradiated with 2000 mJ / cm ² of ultraviolet rays After curing, 1 ml of liquid crystal (Merck, MLC-6866-100) is added, placed in an oven at 120 ° C. for 1 hour, and then left at room temperature for 0.5 hour. Only the liquid crystal was taken out from the sample bottle after the treatment, put in the liquid electrode LE21 (manufactured by Ando Electric), and measured by measuring the specific resistance of the liquid crystal after 4 minutes at a measurement voltage of 10V with an electrometer R-8340 made by Advantest. . Specific resistance values are shown in Table 1.

Sealing agent adhesion strength test 1 g of 5 μm glass fiber is added as a spacer to 100 g of liquid crystal sealing agent and mixed and stirred. This liquid crystal sealing agent was applied on a glass substrate of 50 mm × 50 mm, and a glass piece of 1.5 mm × 1.5 mm was bonded on the liquid crystal sealing agent. In Example 1 and Comparative Examples 1, 2, 3, and 4, Irradiates ultraviolet rays of 3000 mJ / cm ^{2 with} a UV irradiator and puts it in a 120 ° C. oven for 1 hour to cure, and in Example 2 and Comparative Examples 5, 6, 7, and 8, put it in a 120 ° C. oven for 1 hour. It was hardened by doing. The shear adhesive strength of the glass piece was measured. The results are shown in Table 1.

Moisture Resistance Reliability Test 1 g of 5 μm glass fiber is added as a spacer to 100 g of liquid crystal sealant, and mixed and stirred. This liquid crystal sealing agent was applied on a glass substrate of 50 mm × 50 mm, and a glass piece of 1.5 mm × 1.5 mm was bonded on the liquid crystal sealing agent. In Example 1 and Comparative Examples 1, 2, 3, and 4, Irradiates ultraviolet rays of 3000 mJ / cm ^{2 with} a UV irradiator and puts it in a 120 ° C. oven for 1 hour to cure, and in Example 2 and Comparative Examples 5, 6, 7, and 8, put it in a 120 ° C. oven for 1 hour. It was hardened by doing. Thereafter, the glass piece was left for 24 hours under the conditions of a temperature of 121 ° C., a pressure of 2 atm, and a humidity of 100%, and the shear adhesive strength of the glass piece was measured. The results are shown in Table 1.

Curability test 1 g of each of the liquid crystal sealants of Examples and Comparative Examples was placed on a glass substrate of 50 mm × 50 mm, cured by placing in an oven at 120 ° C. for 1 hour, and the degree of cure was measured by measuring Shore D hardness. . The results are shown in Table 1.

Time-dependent change test About 2 g of each liquid crystal sealing agent of an Example and a comparative example was left to stand in a 25 degreeC test room, and the viscosity change was tracked. The evaluation results based on the rate of increase in viscosity are shown in Table 1.

Table 1
Viscosity Liquid crystal contamination Adhesive strength Moisture resistance reliability Curability Temporal change
(Specific resistance value) (Adhesive strength) (Viscosity)
Example 1 190 Pa · s ○ ○ ○ ○ ○
Example 2 110 Pa · s ○ ○ ○ ○ ○
Comparative Example 1 160 Pa · s ○ ○ △ × ○
Comparative Example 2 160 Pa · s ○ ○ ○ × ○
Comparative Example 3 190 Pa · s ○ ○ ○ × ×
Comparative Example 4 220 Pa · s ○ △ △ ○ ×
Comparative Example 5 50 Pa · s ○ ○ ○ × ○
Comparative Example 6 60 Pa · s ○ ○ ○ × ○
Comparative Example 7 60 Pa · s ○ ○ × ○ ×
Comparative Example 8 110 Pa · s ○ ○ ○ × ○

note)
Specific resistance value: ○ 1.0E + 12 or more
△ 1.0E + 11 ~ 1.0E + 12
× 1.0E + 11 or less

Adhesive strength: ○ 60 MPa or more
Δ 20 MPa to 60 MPa
× 20 MPa or less

Curability: ○ 60 or more Δ 20-60
× 20 or less

Change over time (viscosity): ○ Thickening rate 20% or less
△ Thickening rate 20% ~ 40%
× Thickening rate 40% or more

  As shown in Table 1, the basic properties required for the liquid crystal sealant such as liquid crystal contamination and adhesive strength are good in both the examples and the comparative examples. However, with respect to characteristics such as curability, change with time, and moisture resistance reliability, none of the comparative examples is compatible, but both are compatible in the examples. Therefore, it can be said that the liquid crystal sealant of the present invention has low contamination with respect to liquid crystal throughout the process, is excellent in application workability to a substrate, stability over time, and is excellent in moisture resistance reliability.

Claims (9)

A liquid crystal sealant comprising (a) an epoxy resin, (b) isophthalic acid dihydrazide and (c) an aliphatic hydrazide compound. The liquid crystal sealant according to claim 1, wherein the aliphatic hydrazide compound of component ( c) is an aliphatic dihydrazide. The liquid crystal sealant according to claim 1 or 2, further comprising (d) a photocurable resin and (e) a photoradical polymerization initiator in addition to the component (a), the component (b), and the component (c). The liquid crystal sealant according to claim 3, wherein the photocurable resin as the component (d) is an acrylic resin. The liquid crystal sealant according to claim 3 or 4, wherein the photocurable resin as the component (d) is an epoxy acrylate resin. The liquid crystal sealing agent according to any one of claims 1 to 5, further comprising (f) a silane coupling agent. Furthermore, (g) The liquid-crystal sealing compound of any one of Claims 1 thru | or 6 containing the inorganic filler whose average particle diameter is 3 micrometers or less. The liquid crystal sealant according to any one of claims 1 to 7, having a viscosity of 250 Pa · s or less. A liquid crystal display cell sealed with a cured product obtained by curing the liquid crystal sealing agent according to claim 1.